mid-ocean ridge-longest chain of mountians in the world
sonar-device that maps tha ocean floor
sea-floor spreading-molten lava erupting from the mid-ocean ridge forming new oceanic crust
deep ocean trenches-places where old oceanic crust sinks back in the mantle
subduction-procces where old oceanic crust sinks back into the mantle
Outline
Mapping the mid-ocean ridge
Using sonar to map the mid-ocean ridge
Evidence for Sea-Floor Spreading
1960 Harry Hess
ocean floor like a conveyor belts
Evidence from Magnetic Stripes
magnetic strips
some rocks formed when the Earths magnetic field switched
Evidence from Drilling Samples
rocks farther from the ridge were older
younger ones were closer to the ridge
Evidence from Molten Material
molten rocks
shaped like pillows
Subduction at deep ocean trenches
deep-ocean trenches are places where old oceanic crust sinks
oceanic crust bends downward when subduction occurs
new oceanic crust is hot but eventtually cools down and becomes more dense
Table of Contents
1.4 Sea-floor spreading
Vocabulary
mid-ocean ridge-longest chain of mountians in the world
sonar-device that maps tha ocean floor
sea-floor spreading-molten lava erupting from the mid-ocean ridge forming new oceanic crust
deep ocean trenches-places where old oceanic crust sinks back in the mantle
subduction-procces where old oceanic crust sinks back into the mantle
Outline
Mapping the mid-ocean ridge
Evidence for Sea-Floor Spreading
Evidence from Magnetic Stripes
Evidence from Drilling Samples
Evidence from Molten Material
Subduction at deep ocean trenchesSubduction and Earth's Ocean